Gas turbine engines used to drive generators for generating electric power provided by utility companies and other large concerns require large amounts of combustion air. Since these turbines are installed near or at ground level, it is necessary to filter the combustion air because ground level air is ladened with particulate matter that will damage a turbine engine if ingested.
In order to remove particulate matter from combustion air, it is the practice to provide an air inlet enclosure which is partitioned into a dirty or upstream air chamber and a clean or downstream air chamber. The partition is in the form of a horizontal panel having air intake openings therethrough. Aligned with each air intake opening is an individual air filter. According to the present practice, each filter includes a filter media sandwiched in a cage of expanded metal. Eventually, the filter media becomes clogged with airborne particles. When this happens, the filter media must be replaced in order to maintain the efficiency of the gas turbine using the filtered combustion air. Each enclosure contains many air filters. For example, in one installation, there are 864 separate air filters spaced two feet apart. Since air filters with expanded metal cages are relatively expensive and because there are numerous air filters for each location, replacement costs are relatively high. Moreover, due to the millions of air filter elements for vehicles which are replaced and disposed of each year, disposing of air filters has become an environmental issue with respect to any type of air filter. Since new regulations now make it difficult to dispose of air filters with metal components, there is a need for air filter arrangements, used with large gas turbines, which do not require filter media with metallic components.